This was really enjoyable. This is more of a puzzle game, as you have to carefully consider where to "spend" you slime and in what order. And getting it back where you can is also an important part. It really made me analyze the level layout and think about what enemies to tackle first. I like it :D
The biggest standout for me are the graphics. Not only the lightning and decorations but the way the entire world is visible from the get-go. You can see the lower levels and know what's coming to you. You can also see the final boss the entire time. And a nice effect of this is that you still see the fireworks when you go back to the menu. Wonderful ^^
The controls can be a bit difficult to work with at times, especially when you are bigger and try to squash small slimes. But this isn't really a deal-breaker as you can just leave behind slime you don't need for a particular fight.
All in all, I really had fun :)